This is true, nearly every book has at least some useful or insightful bits, but our time is limited. If you're reading one book that's mostly uninteresting, you're also not reading all the other books that you could be reading instead. Now I'm not advocating for minmaxing your life down to the point of insanity, but I do think it's sensible to try and pick up good books over bad books — whatever that means to you.
The last part is most important: whatever that means to you.
I've read books that I thought were great at presenting some key concept. Other people would disagree. The key thing is that different people perceive and absorb information in different ways, no one book will appeal to everyone.
